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The Axial Skeleton


Skeletal system includes both:

      Axial skeleton


    Auditory ossicles and hyoid bone

    Vertebral column

    Thoracic cage

      Appendicular skeleton

    Pectoral and pelvic girdles

    Upper and lower limbs


The skull

      Consists of the cranium and the bones of the face

    The cranium encloses cranial cavity

    Facial bones surround and protect the entrances to the respiratory and digestive tracts

      Superficial landmarks include the sutures






Focus: The Individual Bones of the Skull Cranial Bones

      one occipital bone

    foramen magnum

      two parietal bones

      one frontal bone

    frontal sinuses


The Axial Skeleton



Facial bones

      Maxillary bones


      Palatine bones

      Nasal bones




      Largest facial bones

      Form the upper jaw and most of the hard palate


Palatine and Nasal Bones

      Palatine bones

    Small L shaped bones

    Form the posterior hard palate and floor of the nasal cavity

      Nasal bones

    Superior border of external nares


Vomer, Zygomatic and Lacrimal bones


    Inferior portion of the nasal septum

      Zygomatic bone

    Temporal process articulates with zygomatic process of temporal bone

      Lacrimal bones

    Smallest bones of the face

    Sit medially in orbit


Mandible and Hyoid bones


    Bone of the lower jaw


    Suspended by stylohyoid ligaments

    Supports the larynx


The orbital and nasal complexes

      Seven bones in the orbital complex

      Nasal complex = bones that enclose the nasal cavities and paranasal sinuses


Skulls of infants and children

      Fontanels permit skulls of infants and children to continue growing



Vertebral column

      Vertebrae, sacrum, coccyx

    7 cervical vertebrae

    12 thoracic vertebrae

    5 lumbar vertebrae

    Sacrum and coccyx are fused vertebrae


Spinal curvature

      Four spinal curves

    Primary (accommodation) curves = thoracic and sacral

    Secondary (compensation) curves = lumbar and cervical


Vertebral anatomy

      Typically has a body and vertebral arch

      Superior and inferior articular processes

      Separated by intervertebral discs


Vertebral regions


    Has distinctive shape

    Large relative size of vertebral foramen

    Costal processes with transverse foramina

    Notched spinous processes


Thoracic vertebrae

      Heart-shaped body

      Long slender spinous processes

      Articulations for ribs



Lumbar vertebrae

      Most massive

      Least mobile

      Subjected to great stresses



      Protects reproductive, digestive and urinary organs

      Articulates with pelvic girdle and fused elements of coccyx


Thoracic cage

      Thoracic vertebrae



    Ribs and sternum forms the rib cage


The ribs

      Ribs 1-7 are attached to vertebrae

      8-12 are vertebrochondral ribs

      11-12 are floating ribs


Typical rib

      Has a head, neck, tubercle and a body

      Costal groove marks pathway of blood returning to the heart


The Sternum consists of



      Xiphoid process